Calendar

Most mobile devices offer a calendar app and there are other apps also available.
The most useful calendars allow synchronisation across all your devices so that editing on one device, say a computer, is reflected on the mobile phone calendar.
This means that appointments can be entered on the most convenient device at the time and automatically updated on all.
It is also possible to share calendars between family members or friends so that clashes of appointments are avoided.
Electronic calendars can also be set to provide reminders of appointments.

Music

There are a number of apps that support music writing or playing.
These can be as simple as a guitar tuner app to keyboards, synthesisers and music sequencers.

Streaming Music

Streaming music provides free or paid services where music of the user's choice are sent continuously to the selected device.
The streaming service will use significant data so care should be taken to understand how much it will cost.

Cloud Based Documents

There are apps that allow creation of documents that can be created in a cloud service. These documents can be accessed and edited across all synchronised devices so that a document is available anywhere internet access is provided.

Smart Home Control

With the development of the so called 'smart' home, devices in the home can be controlled by an app in a mobile phone or tablet.
This requires that the home has wifi operating 24/7 so that the phone and devices can be always connected.

There are significant security risks as the 'smart' devices have varying in-built security.
Many of the voice operated controllers for smart homes process requests on a remote computer so that personal data is given to the service provider.

Smart devices also work on a variety of systems so that they may not be compatible with each other.

While there are many advantages touted, it needs careful evaluation as the cost to implement may be $5,000 and up depending on how sophisticated an installation is purchased.

If an installation is made on a new build the cost may go much higher, again depending on the type of installation.